SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956107b5f0c196a15d09ffa087ad01d79c2ce2172064b73e1b41dba74844bbb0' 
  AND token = 'vs2FFMHz7sN8o14YnDR01JsFwW9k032zD+uRA22vlg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}